The prefrontal cortex is a region of the brain that acts like a filter, keeping any irrelevant thoughts, memories and perceptions from interfering with the task-at-hand.
In a new study, researchers at the University of Pennsylvania have shown that inhibiting this filter can enhance unfiltered, creative thinking.
To test whether blocking this filter (resulting in less cognitive control) could be helpful in certain circumstances, the researchers designed an experiment that inhibited the activity of the left prefrontal cortex in adults while they completed a creative task.
In the task, participants looked at pictures of everyday objects and were asked to quickly think of uses for them that were out of the ordinary, such as using a baseball bat as a rolling pin.
Participants were shown a sequence of 60 objects—one every nine seconds—and the researchers measured how long it took for them to think of a valid response, or if they were unable to think of anything before the next picture appeared.
“When we use objects in daily life, our cognitive control helps us focus on what the object is typically used for and ‘filters out’ irrelevant properties,” said Dr. Evangelia Chrysikou, an assistant professor at the University of Kansas.
“However, to come up with the idea of using a baseball bat as a rolling pin, you have to consider things like its shape and the material it’s made of.”
The researchers hypothesized that high levels of cognitive control would be a disadvantage while trying to come up with these kinds of uncommon uses.
“The real takeaway,” said lead researcher Sharon Thompson-Schill, Ph.D., director of Penn’s Center for Cognitive Neuroscience, “is that when you give people a task for which they do not know the goal — such as showing them an object and asking, ‘What else can you do with this thing’ — anything that they would normally do to filter out irrelevant information about the object will hurt their ability to do the task.”
The method used in the study is called transcranial direct current stimulation, or tDCS. It involves passing a weak electrical charge through the brain, aiming its path so that it intersects with areas thought to be associated with an ability or behavior.
Participants were first split into groups corresponding to three experimental conditions: One would receive tDCS to their left prefrontal cortex while completing the task, another would receive it to their right prefrontal cortex and a third would receive what amounted to a placebo. tDCS produces a slight tingling sensation on the scalp when it is first applied, so those in the third group received only a brief period of stimulation before the task began, instead of throughout.
There was a significant difference between those who received tDCS to their left prefrontal cortex and those who didn’t when completing the uncommon-use task.
The right prefrontal cortex and placebo groups couldn’t come up with uncommon uses for an average of 15 out of 60 objects. However, those whose left prefrontal cortices were being inhibited only missed an average of eight. They were also able to provide correct responses an average of a second faster than the former two.
“A second faster difference is huge in psychology research. We’re used to seeing differences measured in milliseconds,” Thompson-Schill said. “This is probably the biggest effect I’ve seen over my 20 years in research.”
“There are things that are important to not filter, in particular when you are learning,” she said. “If you throw out information about your environment as being irrelevant, you miss opportunities to learn about those things.”
The study is published in the journal Cognitive Neuroscience.
Source: University of Pennsylvania